新型温度敏感性自组装胶束P(NiPAAm-co-DMAA)-co-P(L-Ala)的合成和性能

通过原子转移自由基聚合(ATRP)合成了一种带有活性—NH2基团的温度敏感性亲水型共聚物P(NiPAAm-co-DMAA), 并将其作为引发剂, 合成了P(NiPAAm-co-DMAA)-co-P(L-Ala), 其分子量分布(PDI)在1.3左右. 聚合物通过自组装形成纳米胶束. 透射电镜(TEM)结果表明, 胶束大小200~300 nm, 具有明显的核壳结构. 共聚物的最低临界溶解温度(LCST)为45.5 ℃. 温度低于LCST时, 聚合物溶解形成胶束; 高于LCST时, 胶束解离, 聚合物不溶. 聚合物对温度的响应是快速而可逆的.     

Characterization of Mn—Doped Ba1—xSrxTiO3 Thin Films Prepared by the Sol—Gel Method

Undoped and Mn-doped Ba1-xSrxTiO3(BST) thin films have been fabricated on Pt/Ti/SiO2/Si by an aqueous acetate sol-gel method.The BST stock solution can be easily mixed with an aqueous metal ion solution and is stable at room temperature.The annealing temperature of the doped and undoped films is between 650-750℃.The x-ray photoelectron spectra results show that the Mn2p3/2 valence state in the BST is the sampe as that of the original Mn(Ⅱ） dopant,The dielectric constant of the BST thin films can be increased to 800,and the loss tangent can be decreased to 0.01 due to the Mn(Ⅱ） doping.The leakage current of the BST films can also be greatly reduced.